BS only put in about $3bn of their funds. The rest came from bonds issued. These were offered at an eye-watering interest rate (over 6% p.a.) to be able to attract sufficient investor interest. 6% is a huge amount in the current market. Investors looking for yield were all over it.
These billions of dollars of junk bonds are now Refinitiv debt. Yes, BS used F&R/Refinitiv as collateral for the bonds. Although even as junk bonds, these are particularly junky, with BS retaining some very favourable terms that may bite investors if Refinitiv ever fails to, or looks like it may fail to, pay the coupon.
So the risk is largely with the bond Investors, who are betting that Refinitiv have the revenue to pay the coupon. To meet these huge debt obligations, BS/Refinitiv has to cut costs ASAP. First coupon due soon.
Refinitiv/F&R always has very low growth on the top line. So massive cuts must be made on the bottom line. And quite likely, profitable parts of the business may be sold off (TWeb, Dealing, FXall) entirely to lower debt or return funds to BS (and proportionally, TR)
Once the costs have been taken out, BS will sell their stake (in part or in whole) and recover a multiple of their initial few billion invested. This is their bread and butter business. BS know exactly what they are doing. Their profit, Refinitiv employees pain.